The present invention relates generally to a delivery system which is adapted to dispense a predetermined amount of material and, in particular, to a delivery system in which the amount of material dispensed is a function of the weight of an associated subject.
It is often desired to control the amount of a material supplied to a subject such as a human being or an animal based on the weight of the subject. Generally, this requires that the subject must be weighed, and then the amount to be supplied to the subject must be calculated based on the subject's weight and any weight conversion factors. Once this amount has been calculated, a delivery device, such as a syringe, can be filled with the desired amount and then either supplied orally or injected into the subject. Such a procedure can be relatively time consuming, especially when the number of subjects to be dosed is relatively large, as is often the case in laboratory situations.
An automatic dispensing system is available from the Hamilton Company of Reno, Nevada. This dispensing system includes a programmable microprocessor control which is adapted to control a delivery device connected to a supply of the material to be dispensed. The control automatically dispenses a predetermined amount of the material in accordance with parameters programmed into the unit by the operator. While such a system eliminates the need for measuring the individual dosages to be dispensed, an operator is still required to calculate the amount of each dosage.
Examples of dispensing systems which are adapted to supply a material to a subject based on the weight of the subject are disclosed in U.S. Pat. Nos. 3,003,823 to Cohen and 3,656,478 to Swersey. The Cohen patent discloses a weight control apparatus for automatically supplying food to an animal in order to maintain the animal at a predetermined weight. When the weight of the animal falls below the predetermined weight, a feeding mechanism is activated to continuously supply food to the animal at a selected rate until the animal reaches the predetermined weight.
The Swersey patent discloses an infusion monitor which is adapted to supply an infusing liquid into a patient at either a high rate of speed or a low rate of speed, depending upon the weight of the patient. For example, with the infusion monitor operating at the normal low speed, if the weight of the patient decreases below a preset value, the infusion monitor is switched to the high speed. When the weight of the patient subsequently returns to the preset value, the infusion monitor switches back to the low speed.